Laboratory tests on two samples of pitchblende gravity concentrates received from South Alligator Uranium N.L. and assaying 50 percent U308, show that the material can be further upgraded to 70 percent U306 by removal of iron pyrite by flotation; the latter constituting about 30 percent by weight of the gravity concentrate. Grinding prior to flotation is not necessary and batch treatment in a unit flotation cell would be practicable. Recoveries of over 90 percent of both the uranium and the pyrite would be expected in practice by this method.